How did my household acquire thousands of simoleons overnight?

@Turjan , thank you very much! I've been playing with Story Progression for a long time now, but I didn't even notice inheritance was a thing that came with it. It's possible that some of my previous households had received money this way, but they were already rich when it happened so I didn't notice. This was a very noticeable change from 850 to over 20,000!